This is rather a very simple task, follow below steps to do it.
Step 1: Login using your creator credentials
Step 2: Go to Create section using the left menu
Step 3: Create a topic and give it desired name and description
Step 4: Now inside this topic you can create your Interactive Deck. Under Add Content Header, click on “Deck”. It will open a modal. In this modal, click on “Create a New Deck” button.
Step 5: Your Interactive Deck has been initialized, now you can start creating content inside this Deck.
Step 6: Don’t forget to Save/Download the deck once you are done.